Improvement in steam slide-valves



NITE @Ii J. HALL, OF SALEM, OHIO.

IMPROVEMENT IN STEAM SLIDE-VALVES.

Specificnl ion forming pai-t of Letters I'atent No. 82,520, dated September 29, 1868.'

To all 'whom it may concern Be it known that I, J. It. I-IALL, of Salem, in the county of Columbiana and State of Ohio, have invented a new and useful Improvement in Balanced Slide-Valves; and I do hereby declare that the following is a full, clear, and exact description thereof, whichwill enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l represents a longitudinal vertical section on the line .fr .r of Fig. 2. Fig. 2 represents a horizontal section on the line y y of Fig. l. Fig. 3 represents a vertical transverse section on the line z z of Fig. 2.

Similar letters of reference indicate correspondin g parts.

The object of this invention is to provide a balance-valve that will be equally balanced at all times and under the varying conditions arising from the action of the steam on entering and exhausting from the cylinder.

It consists in the construction of cylinders in the back of the valve, and the provision of the said cylinders with plungers having recesses in the top, opening to the inner face of steam-chests, having areas equal to the different parts of the valve exposed to an upward pressure, and openings to admit the live steam to them, and provided with packing-joints to control the steam in passing to and from the said recesses, as will be more fully described on reference to the accompanying drawings, wherein- A represents the valve-chest, B the valveseat, and C C the ports. D represents the valve, and E a hood or bridge, under which the valve works and against which the downward pressure is obtained.l The valve is provided with a longitudinal channel, a, for re-- ceiving the live steam through the passage al, and with transverse channels a2 and a3, for supplying it to the ports C and C.

b, b1, and b2 represent short cylindrical chambers provided in the top of the valve, in which are fitted plun gers d, dl, and d2, having recesses in the top ends, which are fitted to work steam-tight against the under face of the bridge E or valve-chest.

In the said cylinders, in the bach of the valve, followers c, cl, and c2 are provided,

which are uniformly borne upward by elliptic or other suitable springs, f, sufficiently to cause the pistons to bear fairly on the bridge. Annular recesses are formed in the faces of these plungers, between which and the walls of the cylinders corresponding annular projections 011 the under side of the pistons fit, but lea-ving sufiicient space for rings of iiexible and elastic packing g to be inserted, to preserve steam-tight joints between the plungers and the walls of the cylindrical chambers to prevent the escape ofthe steam at the open ends ofthe said cylinders. Communication with the recesses in the upper ends of the plungers for the live steam under the valve is made through the central passages h, h1, and h2.

The recess in the piston dl is intended to be filled with live steam from the supply-passage al, which, bearing against the lower face of the bridge, will balance the upward pressure on the live-steam passage a under the valve, and is always open to the live steam. The area of the recess in the said piston d' should be enough greater than the area of the livesteam passage a to keep a fair bearing of the valve upon the valve-seat-say about twentyfive per cent.

As the ports C and C are alternately opened and closed, the upward pressure on the lips of the valves varies according to the position of the valves, alternating between the full pressure due to the area of the ports and none when the exhaust has taken place, from which, in the valves as ordinarily constructed, great inequality of friction takes place, and to avoid which is the principal object of my invention 5 and to this end I have arranged the pistons d and d2 at each end of the valve, which operate as follows:

When the port is open to the steam cylinder, communication is also opened with the recesses in the said pistons through the holes h and h2. The area of each recess is calculated to be the same as the area of each port. The lips of the valve being also provided with rections, whether little or great, while the ports are open to the steam, and, when open to the exhaust, the steam will also exhaust from the recesses, thereby effecting an equal balancingpressnre under the ends of the valves, and removin g the same when the said upward pressure is removed, the exhaust is effected into the valve-chamber, and may be carried off in any desired manner.

The holes through the plun gers may be made so small that the leakage which may occur from imperfection of the seat against the bridge will weaken the pressure in the recesses between the plungers and the bridge, and thus the plunger will be niade to bear harder against the bridge, and thereby sooner seat itself. rlhe recesses nia-y also be niade of any shape other than annular, if desired.

Having thus described my invention, I elai 1n as new and desire to secure by Letters Patent- The arrangement of the valy'e D, with its chambers b b1 b2, the recessed followers c cl c2, and the pistons d d1 d2 with the central passages h h1 h2 and the passages al a2 a3, whereby to balance the pressure of steam upon the valve, substantially as herein set forth.

J. R. HALL.

Vitnesse;

GEO. XV. FIsHER, HARRY B. GARRIGURS. 

